Publications by authors named "Erol Ozgur"

Background/aim: Griscelli Syndrome Type 2 (GS-2) is a rare, inherited immune deficiency caused by a mutation in the gene. The current treatment consists of hematopoietic stem cell transplantation, but a lack of suitable donors warrants the development of alternative treatment strategies, including gene therapy. The development of mutation-specific clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 gene editing technology has opened the way for custom-designed gene correction of patient-derived stem cells.

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RAG2 deficiency is characterized by a lack of B and T lymphocytes, causing severe lethal infections. Currently, RAG2 deficiency is treated with a Hematopoietic Stem Cell transplantation (HSCT). Most conditioning regimens used before HSCT consist of alkylating myelotoxic agents with or without irradiation and affect growth and development of pediatric patients.

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Inflammatory bowel disease (IBD) is characterized by a chronically dysregulated immune response in the gastrointestinal tract. Bone marrow multipotent mesenchymal stromal cells have an important immunomodulatory function and support regeneration of inflamed tissue by secretion of soluble factors as well as through direct local differentiation. CXCR4 is the receptor for CXCL12 (SDF-1, stromal-derived factor-1) and has been shown to be the main chemokine receptor, required for homing of MSCs.

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Purpose: This research endeavors to improve tumor localization in minimally invasive surgeries, a challenging task primarily attributable to the absence of tactile feedback and limited visibility. The conventional solution uses laparoscopic ultrasound (LUS) which has a long learning curve and is operator-dependent.

Methods: The proposed approach involves augmenting LUS images onto laparoscopic images to improve the surgeon's ability to estimate tumor and internal organ anatomy.

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Clinical Relevance: Currently eye examinations are usually based on autorefraction followed by subjective refraction (SR) with a phoropter. An automated phoropter that can also perform autorefraction may facilitate the optometric workflow.

Background: The efficiency and feasibility of an objective autorefraction and correction system are assessed by comparing objective refractive measurements with SR on the same subjects and evaluating the visual acuity (VA) values obtained after the objective refractive measurement and correction.

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Article Synopsis
  • - Small GTPases, particularly the Rab family, are crucial for various cellular functions, including membrane trafficking and maintaining cell structure, with nearly 70 known human members involved in these processes.
  • - Mutations in Rab genes can lead to a range of genetic disorders, including neurodegenerative diseases like Parkinson's and Alzheimer's, immune disorders, and certain cancers, highlighting their importance in health.
  • - The text discusses potential therapeutic strategies, including stem cell gene therapy and using Rabs as biomarkers, to treat cancer and other diseases while emphasizing the need for further research into Rabs' roles in complex conditions like diabetes.
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Coronavirus Disease-19 (COVID-19) is a highly contagious infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The development of rapid antigen tests has contributed to easing the burden on healthcare and lifting restrictions by detecting infected individuals to help prevent further transmission of the virus. We developed a state-of-art rapid antigen testing system, named DIAGNOVIR, based on immune-fluorescence analysis, which can process and give the results in a minute.

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We present the performance analysis and specifications of a portable auto-phoropter system that can be employed for fast refractive assessment of a large population. A customized Shack-Hartmann wavefront sensor is developed to accurately measure the defocus and astigmatism of the eye within ±10 and ±6, respectively. Three fluidic lenses are designed to correct the vision in real time.

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Despite a vast amount of different methods, protocols and cryoprotective agents (CPA), stem cells are often frozen using standard protocols that have been optimized for use with cell lines, rather than with stem cells. Relatively few comparative studies have been performed to assess the effects of cryopreservation methods on these stem cells. Dimethyl sulfoxide (DMSO) has been a key agent for the development of cryobiology and has been used universally for cryopreservation.

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Tunable spherical fluidic lenses are among the most essential components in adaptive optics. However, fabricating cylindrical tunable lenses has proven more challenging, mainly due to the difficulty in eliminating the defocus component. We demonstrate a parametric approach to minimize the defocus in cylindrical tunable fluidic lenses.

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Background: Griscelli syndrome type 2 (GS-2) is a rare, autosomal recessive immune deficiency syndrome caused by a mutation in the RAB27A gene, which results in the absence of a protein involved in vesicle trafficking and consequent loss of function of in particular cytotoxic T and NK cells. Induced pluripotent stem cells (iPSC) express genes associated with pluripotency, have the capacity for infinite expansion, and can differentiate into cells from all three germ layers. They can be induced using integrative or non-integrative systems for transfer of the Oct4, Sox2, Klf4, and cMyc (OSKM) transcription factors.

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Background: Previous work in augmented reality (AR) guidance in monocular laparoscopic hepatectomy requires the surgeon to manually overlay a rigid preoperative model onto a laparoscopy image. This may be fairly inaccurate because of significant liver deformation. We have proposed a technique which overlays a deformable preoperative model semi-automatically onto a laparoscopic image using a new software called Hepataug.

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Chalcogenide materials are promising for optical resonant mode tuning of whispering gallery mode (WGM) microresonators due to their high nonlinearity. In this study, this phenomenon was demonstrated for -coated toroidal microresonators using an optical postprocess, which utilizes the intrinsically photosensitive property of the coating. A signal laser was used to illuminate the resonator for permanent tuning of the WGMs in a sensitive manner.

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Augmented Reality (AR) in monocular liver laparoscopy requires one to register a preoperative 3D liver model to a laparoscopy image. This is a difficult problem because the preoperative shape may significantly differ from the unknown intraoperative shape and the liver is only partially visible in the laparoscopy image. Previous approaches are either manual, using a rigid model, or automatic, using visual cues and a biomechanical model.

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Clean sport competition is of significant concern to many governments and sporting organizations. Highly sensitive and rapid sensors are needed to improve the detection of performance enhancing drugs in sports as athletes take diuretics to dilute the concentration of drugs in their urine and microdose under the detectable limits of current sensors. Here we demonstrate, using frequency locked microtoroid optical resonators, a 3 orders of magnitude improvement in detection limit over the current gold standard, mass spectrometry, for the common performance enhancing drug, human chorionic gonadotropin (hCG).

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Purpose: Augmented reality for monocular laparoscopy from a preoperative volume such as CT is achieved in two steps. The first step is to segment the organ in the preoperative volume and reconstruct its 3D model. The second step is to register the preoperative 3D model to an initial intraoperative laparoscopy image.

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Metal films covered with ultrathin lossy dielectrics can exhibit strong interference effects manifested as the broad absorption of the incident light resulting in distinct surface colors. Despite their simple bilayer structures, such surfaces have only recently been scrutinized and applied mainly to color printing. Here, we report the use of such surfaces for colorimetric detection of ultrathin dielectrics.

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Early detection of pathogens or their virulence factors in complex media has a key role in early diagnosis and treatment of many diseases. Nanomolar and selective detection of Exotoxin A, which is a virulence factor secreted from Pseudomonas aeruginosa in the sputum of Cystic Fibrosis (CF) patients, can pave the way for early diagnosis of P. aeruginosa infections.

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Background: Laparoscopic liver surgery is seldom performed, mainly because of the risk of hepatic vein bleeding or incomplete resection of the tumour. This risk may be reduced by means of an augmented reality guidance system (ARGS), which have the potential to aid one in finding the position of intrahepatic tumours and hepatic veins and thus in facilitating the oncological resection and in limiting the risk of operative bleeding.

Methods: We report the case of an 81-year-old man who was diagnosed with a hepatocellular carcinoma after an intraabdominal bleeding.

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On-chip high-Q microcavities possess significant potential in terms of integration of optical microresonators into functional optoelectronic devices that could be used in various applications, including biosensors, photonic-integrated circuits, or quantum optics experiments. Yet, despite the convenience of fabricating wafer-scale integrated microresonators with moderate Q values using standard microfabrication techniques, surface-tension-induced microcavities (STIMs), which have atomic-level surface roughness enabling the observation of Q values larger than 10, could only be produced using individual thermal treatment of every single microresonator within the devised area. Here, we demonstrate a facile method for large-scale fabrication of silica STIMs of various morphologies.

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This review targets diversified oligonucleotide-based biodetection techniques, focusing on the use of microresonators of whispering gallery mode (WGM) type as optical biosensors mostly integrated with lab-on-a-chip systems. On-chip and microfluidics combined devices along with optical microresonators provide rapid, robust, reproducible and multiplexed biodetection abilities in considerably small volumes. We present a detailed overview of the studies conducted so far, including biodetection of various oligonucleotide biomarkers as well as deoxyribonucleic acids (DNAs), ribonucleic acids (RNAs) and proteins.

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Mictoroids, as optical biosensors, can provide beneficial biosensing platforms to understand DNA alterations. These alterations could have significant clinical importance, such as the case of Pseudomonas aeruginosa, which is a commonly found pathogen in Cystic Fibrosis (CF) patients-causing poor prognosis by undergoing mutations during disease steps, gaining virulence and drug resistance. To provide a preliminary diagnosis platform for early-stage bacterial mutations, biosensing with a selective microtoroid surface was suggested.

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Although label-free biosensors comprised of optical microcavities inherently possess the capability of resolving molecular interactions at individual level, this extreme sensitivity restricts their convenience for large scale applications by inducing vulnerability towards non-specific interactions that readily occur within complex media. Therefore, the use of optical microresonators for biosensing is mostly limited within strictly defined laboratory conditions, instead of field applications as early detection of cancer markers in blood, or identification of contamination in food. Here, we propose a novel surface modification strategy suitable for but not limited to optical microresonator based biosensors, enabling highly selective biosensing with considerable sensitivity as well.

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A facile method to coat silica surfaces with THPMP is introduced, forming simultaneously a protein resistant and bioconjugable surface. The coating is experimentally identified and its anti-fouling and bioconjugable characteristics are demonstrated.

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A change in the intracellular free Ca(2+) concentration ([Ca(2+)]i) functions as a transmitter for signal transduction and shows a broad temporal pattern. Even genetically homogeneous cell types show different Ca(2+) response patterns under permanent agonist stimulation. In Ca(2+) signaling, the dynamics of the Ca(2+) release from the Ca(2+) channels during continuous agonist stimulation and the simultaneous effect of the pumps are unclear.

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